Volume 27, Issue 4, Pages 547-560 (April 2015) TGIF Governs a Feed-Forward Network that Empowers Wnt Signaling to Drive Mammary Tumorigenesis  Ming-Zhu Zhang, Olivier Ferrigno, Zhe Wang, Mutsuko Ohnishi, Céline Prunier, Laurence Levy, Mohammed Razzaque, Williams C. Horne, Damian Romero, Guri Tzivion, Frédéric Colland, Roland Baron, Azeddine Atfi  Cancer Cell  Volume 27, Issue 4, Pages 547-560 (April 2015) DOI: 10.1016/j.ccell.2015.03.002 Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 1 Interaction of TGIF with Axin1/Axin2 (A) HEK293T cells were transfected with Myc-Axin2 in the presence or absence of Flag-TGIF and treated with control or Wnt3a conditioned media (CM) for 1 hr. Lysates were subjected to anti-Flag immunoprecipitation (IP) followed by immunoblotting (IB) with anti-Myc. In this and all the following experiments, expression of proteins under investigation was determined by direct immunoblotting. (B and C) HEK293T cells were transfected with pG5E1β-Luc together with Gal4-Axin2 and VP16-TGIF mutants (B) or Gal4-TGIF and VP16-Axin2 mutants (C). Luciferase activity was measured, and data were expressed as mean ± SD of three independent samples. (D) HEK293T cells were transfected with Flag-TGIF in the absence or presence of Myc-Axin1 and treated with control or Wnt3a CM for 1 hr. Cell lysates were subjected to anti-Myc immunoprecipitation followed by immunoblotting with anti-Flag. (E) MCF7 or HMLE cells were treated with control or Wnt3a CM for 1 hr, and cell lysates were immunoprecipitated with IgG or anti-TGIF before being analyzed by immunoblotting using anti-Axin1, anti-Axin2, or anti-TGIF. (F) HMLE cells were treated with Wnt3a CM for the indicated times, and cell lysates were immunoprecipitated with anti-TGIF before being analyzed by immunoblotting using anti-Axin1 or anti-Axin2. See also Figure S1. Cancer Cell 2015 27, 547-560DOI: (10.1016/j.ccell.2015.03.002) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 2 TGIF Interferes with the Nucleocytoplasmic Transit of Axin1/Axin2 (A) COS-7 cells were transfected with Flag-Axin2 and GFP-TGIF and immunostained with anti-Flag and DAPI. Scale bars, 100 μM. (B) Wild-type or Tgif1−/− MEFs were immunostained with anti-Axin2 and DAPI. Scale bars, 100 μM. (C) Cytoplasmic or nuclear fractions from wild-type or Tgif1−/− MEFs were immunoblotted with anti-Axin1 or anti-Axin2. Purity of the nuclear and cytoplasmic fractions was verified by immunoblotting using anti-Lamin B or anti-α-tubulin. (D and E) Lysates from wild-type or Tgif1−/− MEFs were immunoprecipitated with anti-β-catenin (D) or anti-CRM1 (E) and analyzed by immunoblotting with the indicated antibodies. See also Figure S2. Cancer Cell 2015 27, 547-560DOI: (10.1016/j.ccell.2015.03.002) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 3 TGIF Interferes with β-Catenin Degradation (A) Lysates from Tgif1+/+ or Tgif1−/− MEFs were immunoprecipitated with IgG or anti-β-catenin and analyzed by immunoblotting using the indicated antibodies. (B) MCF7 cells were transfected with HA-β-catenin or HA-β-catenin.S33Y in the absence or presence of Flag-TGIF, and cell lysates were immunoblotted with anti-HA or anti-Flag. (C) HEK293T cells were transfected with Flag-β-catenin together with Myc-βTRCP and increasing amounts of Flag-TGIF. Association of β-catenin with βTRCP was analyzed by blotting anti-Myc immunoprecipitates with anti-Flag. (D) MCF7-Dox-Myc-TGIF cells were cultured with or without doxycycline (Dox) for 48 hr. Association of β-catenin with βTRCP was determined by blotting anti-βTRCP immunoprecipitates with anti-β-catenin. (E) Tgif1+/+ or Tgif1−/− MEFs were cultured with control or Wnt3a CM for the indicated times, and lysates were immunoblotted with anti-β-catenin, anti-Axin2, or anti-TGIF. (F) Tgif1+/+ or Tgif1−/− MEFs were treated with vehicle or MG132 for 12 hr, and cell lysates were subject to immunoblotting using anti-β-catenin. (G) Expression of β-catenin was analyzed using extracts from mouse mammary glands with the indicated genotypes. (H) Analysis of active (nonphosphorylated) β-catenin levels in mammary glands from Tgif1+/+ or Tgif1−/− mice by immunohistochemistry. The percentage of stained cells in at least 20 independent fields is indicated. The line inside the box shows median percentage. The top and bottom of the box represent upper (third) and lower (first) quartile percentages, respectively. The lines above and below the box show maximum and minimum percentages, respectively. Scale bars, 50 μM. See also Figure S3. Cancer Cell 2015 27, 547-560DOI: (10.1016/j.ccell.2015.03.002) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 4 TGIF Promotes Wnt Signaling (A and B) MCF7 or HMLE cells stably expressing control (sh.Luc) or TGIF (sh.TGIF) shRNAs were cultured with control or Wnt3a CM for 24 hr. Expression of Wnt target genes was analyzed by qRT-PCR (A), and the expression of CyclinD1 or TGIF was determined by immunoblotting (B). (C and D) Expression of Wnt target genes in the mammary glands of mice with the indicated genotypes (eight in each group) was analyzed by qRT-PCR (C), and the expression of CyclinD1 was assessed by immunoblotting (D). (E and F) MWT23 cells stably expressing empty vector or TGIF were treated with vehicle or tamoxifen (Tam) for 5 days, expression of Wnt target genes was analyzed by qRT-PCR (E), and the expression of CyclinD1 or TGIF was determined by immunoblotting (F). Results in (A), (C), and (E) are expressed as mean ± SD of three independent samples. See also Figure S4. Cancer Cell 2015 27, 547-560DOI: (10.1016/j.ccell.2015.03.002) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 5 TGIF Is a Wnt Target Gene (A) Expression of TGIF or β-catenin was assessed by immunoblotting using extracts from mammary glands of MMTV-Wnt1 or Dkk1 mice or liver from Ctnnb1 conditional knockout. (B) HMLE cells were left untreated or treated with control or Wnt3a CM for 24 hr, and chromatin was immunoprecipitated with anti-β-catenin, anti-TCF4, or IgG. Bound chromatin (in control cells) was amplified by PCR and analyzed by 2% agarose gel (left). Bound chromatin in control or Wnt3a-treated cells was analyzed by qRT-PCR. (C and D) HMLE-Dox-HA-β-catenin (C) or HMLE-Dox-Myc-DN-TCF4 (D) cells were treated with or without Dox for 48 hr before being cultured with or without Wnt3a CM for 16 hr. Expression of TGIF protein and mRNA was measured by immunoblotting and qRT-PCR, respectively. (E) MCF7 cells were left untreated or were treated with Wnt3a for different times, and expression of TGIF was assessed by immunoblotting. (F) Expression of TGIF and β-catenin in tissue microarrays including 173 human breast cancer samples was analyzed by immunohistochemistry. The percentages of samples with high expression of TGIF and β-catenin in TNBC and non-TNBC subtypes are shown. Scale bars, 50 μM. (G) MCF7 cells were stably transfected with doxycycline-inducible TGIF (two independent populations) or empty vector and treated with or without Dox for 48 hr. Expression of β-catenin or TGIF was determined by immunoblotting. (H) Kaplan-Meier graph representing the probability of cumulative recurrence-free survival in TNBC patients according to the TGIF expression, low (128) versus high (255). Results in (B)–(D) (right) are expressed as mean ± SD of three independent samples from representative experiments performed at least three times. See also Figure S5. Cancer Cell 2015 27, 547-560DOI: (10.1016/j.ccell.2015.03.002) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 6 Tgif1 Deletion Blocks Wnt1-Induced Mammary Tumors (A) Tgif1+/+, MMTV-Wnt1;Tgif1+/+, or MMTV-Wnt1;Tgif1−/− mice were photographed 3 weeks after the tumors became palpable. (B and C) MMTV-Wnt1 mice with Tgif1+/+, Tgif1+/−, or Tgif1−/− genotypes were palpated twice weekly from puberty onward for 60 weeks, and dates of tumor incidence were recorded (B). For comparison, tumor volumes at sacrifice were shown (C). (D) Whole-mount staining of mammary glands from 4-month-old virgin mice with the indicated genotypes. (E) H&E staining of mammary glands from mice with the indicated genotypes three weeks after tumor formation. Scale bars, 500 μM for (D) and 200 μM for (E). See also Figure S6. Cancer Cell 2015 27, 547-560DOI: (10.1016/j.ccell.2015.03.002) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 7 TGIF Promotes Mammary Tumors by a Mechanism Dependent on Its Ability to Antagonize Axin1/Axin2 (A) Flip-In MWT23 or MWT37 cells carrying one or two copies of TGIF were treated with vehicle or Tam for 5 days. Expression of TGIF was assessed by immunoblotting. (B) Cells (as in A,105) were implanted into mammary fat pad of FVB mice, and tumor volumes were measured at the indicated times. (C) MWT23 cells stably expressing the indicated shRNAs were treated with vehicle or Tam for 5 days. Expression of Axin1, Axin2, or β-catenin was assessed by immunoblotting. (D) Cells (as in C, 5 × 105) were transplanted into mammary fat pad of FVB mice, and tumor volumes were measured at the indicated times. Results in (B) and (D) are expressed as mean ± SD of measurements obtained with six animals in each group. See also Figure S7. Cancer Cell 2015 27, 547-560DOI: (10.1016/j.ccell.2015.03.002) Copyright © 2015 Elsevier Inc. Terms and Conditions

Figure 8 TGIF Promotes Wnt1-Induced Mammary Tumor Formation by a TGF-β-Independent Mechanism (A and B) MWT23 or MWT37 cells stably expressing empty vector, HA-DN-TβRII, or HA-β-catenin.S33Y (A) or empty vector, HA-TGIF, or HA-TGIFΔAxin2 (B) were treated with vehicle or Tam for 5 days. Expression of transfected proteins was determined by immunoblotting (left). Cells (5 × 105) were transplanted into mammary fat pad of FVB mice, and tumor volumes were measured at the indicated times (right). (C) A model depicting the link of TGIF to the Wnt signaling network. Results in (A) and (B) are expressed as mean ± SD of measurements obtained with six animals in each group. See also Figure S8. Cancer Cell 2015 27, 547-560DOI: (10.1016/j.ccell.2015.03.002) Copyright © 2015 Elsevier Inc. Terms and Conditions